Post nasal drip is caused by the over secretion of mucous in the nasal cavity. The constant trickle of mucus in the throat results in triggering the cough reflex. During colds (viral infections), inflammation may occur in the mucosa such that cytokines and inflammatory mediators are released into nasal secretions. These then bathe the throat and cause a sequence of pain/soreness that is much more easily aggravated by innocuous stimuli such as changes in air temperature (cold air) which stimulate the cough reflex. Additionally, the cough reflex can also be stimulated by a dry mouth and/or throat. Desensitization of the cough receptors in the throat is believed to provide antitussive effect via the mechanical action of shielding the receptors from further irritation. Cough receptors have been identified functionally and are present on the sensory nerve endings within the epithelium lining in the larynx and pharynx.
Attempts have been made to alleviate this cough response by compositions such as cough drops, sore throat sprays, and cough syrups. The response of current cough drops is not instant and drops are usually solid doses that must be melted in the mouth and provide no coating of the throat. Sore throat sprays can contain actives that numb the mouth and throat. Sprays normally contain instruction to not swallow so there is no throat coating and no cough relief. Additionally, because they normally contain actives the product cannot be used often as needed. Cough syrups contain actives that must be absorbed by the blood which usually takes about 30 minutes for any type of cough relief, therefore there is no instant relief that is targeted for the throat.
Additionally, it is believed that cough suppression can be enhanced by focused delivery of the active to the site of irritation, the target mucosa. The benefit of targeted delivery such as that which is realized when a spray is used, is that the actives are not lost to irreversible binding to the mucin (via mucoadhesion) before they can reach the target sites.
Therefore, the various embodiments described herein provide for a respiratory preparation that provides instant and on demand cough relief in a portable form that can be used as often as needed. The preparation can be used to target the mouth and/or throat and provide a protective barrier that shields the epithelial cells that line the throat and thus prevents the stimulation of a cough response and/or triggers the flow of saliva and to help to hydrate the mouth and/or throat. The barrier can additionally aid in reducing inflammation of the mouth and/or throat and relive minor pain sometimes associated with a cough and/or sore throat.